Siegfried Adolf Handloser (25 March 1885 – 3 July 1954) was a Doctor, Prof. Dr. med., Generaloberstabsarzt (thee stars, OF-8) of the German Armed Forces Medical Services, Chief of the German Armed Forces Medical Services. He was one of the accused in the Doctors' Trial in Nuremberg—after the main Nuremberg Trials.
Born in Konstanz he had been a member of the German Army Medical Service since the First World War. In 1938, Handloser was promoted to the position of Army Group physician of the Army Group Command 3. In October, 1939, he was named honorary professor.
Yet despite his full knowledge, he had done nothing to stop medical experiments conducted on concentration camp prisoners; this was sufficient to implicate him in the several medical cases dealt with during the Doctors' Trial.
He was convicted by the American Military Tribunal No. I in August, 1947, and sentenced to life imprisonment. This was later reduced to 20 years and, in 1954, he was released. Shortly afterwards, Handloser died of cancer in Munich at the age of 69.